Detection device, exposure apparatus, and device manufacturing method using same

Abstract

A detection device that detects a mark provided on the back side of an object, the detection device includes a first detection unit configured to detect the mark from a surface side of the object; a second detection unit configured to detect a surface position of the object; and a processing unit. The processing unit determines a thickness of the object based on a difference between a first focus position acquired with reference to the position of the mark detected by the first detection unit and a second focus position acquired with reference to the surface position detected by the second detection unit.

What is claimed is: 
     
       1. A detection device that detects a mark provided on the back side of an object, the detection device comprising:
 a first detection unit configured to detect the mark from a front side of the object by using a first light that transmits through the object and is reflected by the mark; 
 a second detection unit configured to detect a surface position of the object by using a second light that is reflected by a part of the front side of the object, the part being a mark-free area of the front side of the object; and 
 a processing unit, 
 wherein the processing unit is configured to acquire a first focus position based on an image of the mark detected by the first detection unit and to acquire a second focus position based on the surface position detected by the second detection unit and to determine a thickness of the object based on a difference between the first focus position and the second focus position. 
 
     
     
       2. The detection device according to  claim 1 ,
 wherein the processing unit determines an offset amount acquired by dividing a preset thickness of the object by the refractive index of the object and acquires the first focus position based on information indicating a focus state of the image of the mark; 
 wherein the information is acquired after moving the object by the offset amount from a position where the second focus position is acquired. 
 
     
     
       3. The detection device according to  claim 1 , wherein the first detection unit illuminates the mark with infrared light. 
     
     
       4. The detection device according to  claim 1 , wherein information regarding the refractive index of the object is input to the processing unit in advance. 
     
     
       5. The detection device according to  claim 1 , wherein the second detection unit illuminates the part of the area with visible light. 
     
     
       6. The detection device according to  claim 1 , wherein the thickness is a geometrical thickness. 
     
     
       7. The detection device according to  claim 1 , wherein the processing unit determines the thicknesses at plural positions based on the first focus position and the second focus position acquired at the plural positions of the object and determines three-dimensional information of the object based on the plural thicknesses. 
     
     
       8. An exposure apparatus that exposes a substrate, the exposure apparatus comprising:
 a detection device that detects a mark provided on the back side of the substrate serving as an object or a mark provided on the back side of a photosensitizer which is applied on the substrate and serves as an object; 
 a substrate holding unit configured to hold the substrate; and 
 a control unit that controls the operation of at least the detection device and the substrate holding unit, 
 wherein the detection device comprises: 
 a first detection unit configured to detect the mark from a front side of the object by using a first light that transmits through the object and is reflected by the mark; 
 a second detection unit configured to detect a surface position of the object by using a second light that is reflected by a part of the front side of the object, the part on which a mark is not provided; and 
 a processing unit, 
 wherein the processing unit is configured to acquire a first focus position based on an image of the mark detected by the first detection unit and to acquire a second focus position based on the surface position detected by the second detection unit and to determine a thickness of the object based on a difference between the first focus position and the second focus position. 
 
     
     
       9. The exposure apparatus according to  claim 8 , wherein information regarding the refractive index of the object is input to the control unit in advance instead of the processing unit. 
     
     
       10. The exposure apparatus according  claim 8 , wherein the control unit periodically acquires the thickness determined by the processing unit, and, when it is determined that the thickness varies, the control unit provides feedback of the thickness to at least one of a device which applies thinning processing to the substrate after exposure processing and a device which applies etching processing to the substrate after exposure processing. 
     
     
       11. The exposure apparatus according to  claim 8 , wherein the control unit periodically acquires three-dimensional information determined by the processing unit based on the thickness, and, when it is determined that the three-dimensional information varies, the control unit provides feedback of the three-dimensional information to at least one of a device which applies thinning processing to the substrate after exposure processing and a device which applies etching processing to the substrate after exposure processing. 
     
     
       12. The exposure apparatus according to  claim 8 , wherein the processing unit determines information indicating a focus state of the image of the mark based on an offset amount acquired by dividing a preset thickness of the object by the refractive index of the object and acquires the first focus position based on information indicating a focus state of the image of the mark;
 wherein the information is acquired after the control unit controls the holding unit to move the object by the offset amount from a position where the second focus position is acquired. 
 
     
     
       13. A device manufacturing method comprising:
 exposing a substrate using an exposure apparatus; and 
 developing the exposed substrate; 
 manufacturing the developed substrate, 
 wherein the exposure apparatus is an exposure apparatus that exposes a substrate, the exposure apparatus comprising: 
 a detection device that detects a mark provided on the back side of the substrate serving as an object or a mark provided on the back side of a photosensitizer which is applied on the substrate and serves as an object; 
 a substrate holding unit configured to hold the substrate; and 
 a control unit that controls the operation of at least the detection device and the substrate holding unit, 
 wherein the detection device comprises: 
 a first detection unit configured to detect the mark from a front side of the object by using a first light that transmits through the object and is reflected by the mark; 
 a second detection unit configured to detect a surface position of the object by using a second light that is reflected by a part of the front side of the object, the part on which a mark is not provided; and 
 a processing unit, 
 wherein the processing unit is configured to acquire a first focus position based on an image of the mark detected by the first detection unit and to acquire a second focus position based on the surface position detected by the second detection unit and to determine a thickness of the object based on a difference between the first focus position and the second focus position. 
 
     
     
       14. A detecting method comprising:
 acquiring a first focus position based on an image of a mark provided on a back side of an object, the image detected by using a first light that transmits through the object and is reflected by the mark; and 
 acquiring a second focus position based on a surface position detected by using a second light reflected by a part of a front side of the object, the part being a mark-free area of the front side of the object; and 
 determining a thickness of the object based on a difference between the first focus position and the second focus position.